Electrical devices or systems need power from a power source to operate. In situations where the characteristics of the power source are incompatible with the characteristics of the power needed by the systems, a controller or converter may be used to manipulate the power source to provide a suitable power for the systems. The controller is usually formed in an integrated circuit (IC) or IC chip.
A switch mode power supply (SMPS) is an arrangement of electrical components, including the IC controller, to provide suitable power to a system. A typical IC usually includes external pins for electrical communication with other components. In an SMPS, the IC may include pins for providing specific functions in the SMPS.
In some cases, new functions for the SMPS may be needed. Existing pins of the IC controller may be unable to carry both existing functions and the new functions. Therefore, to accommodate the new functions, new pins may be added to the IC. However, for some ICs, adding new pins may increase size, cost, or both.